MrsR33 - I'm so sorry you are here. Being betrayed sucks, but SI has been a Godsend for me and many others.
There's a healing library that I recommend reading
Also- get tested for STDs (unfortunately, many WS ["Wayward Spouses"] are not only ok lying to engage in the A, but are also OK lying about the sex that actually happened & whether they used a condom.
I would recommend reading two books: "not just friends" by Shirley Glass and "How to Help your Spouse Heal" by Linda McDonald. Both are pretty universally approved by folks on SI. there are a ton of books out there, but I recommend starting with these.
I would suggest your WH get into some counseling -immediately. He needs to figure out why he did this, why he allowed his own needs to be more important than being a safe and honest partner, etc. You may need therapy too. I would not recommend MC (marriage counseling) this early. MCs tend to focus on the M and not the individual needs of each partner. Some may lead you to believe that you shoulder some blame for your WH's conscious decision to break his promise of monogomy - if you hear only one thing, hear this: the decision to cheat is 100% the cheater's responsibility. HIS CHOICE IS NOT YOUR FAULT... no matter what. It's a CHOICE to lie and deceive the one you love, and to break the promise of monogamy... it's not a mistake and it's not your fault.
Read the healing library, the books, and posts here on SI (including the wayward side, if you feel up to it). You will learn that people who cheat do so because something is broken in them. It's imperative they do the HARD work to figure out why it was Ok to harm you in order to put their needs first. This could take a long time, most folks say healing / reconciliation takes 3-5 years on average (I'm at 8 months and still have no answer as to "why" or "how" my WH could have behaved so selfishly for so long).
Take what helps you on SI and leave the rest behind.
Finally, TAKE CARE OF YOU!!!! Many BS (betrayed spouses) don't practice any self care - they can eat too much or not at all, they have difficulty sleeping, are prone to depression, etc.
It's super important that you eat healthy (I often had to force myself to eat, but protein drinks worked well), be sure to get some exercise, and try to sleep (see a physician if you must).
Again, I am so sorry you are hurt. This is a really painful thing to experience and can be very difficult to get through. It is an emotional trauma (some - not all - exhibit the classic signs of PTSD when they discover the infidelity). You may have nightmares, you may have "mind movies" about your WH and the AP (affair partner), you may have difficulty focusing. You may experience hypervigilence, obsessive thoughts, etc. These are normal, but can be very hard to cope with. You have found SI, and there are a ton of folks here who are happy to provide insight via sharing their own experiences. Need to vent? Do it here (you may want to consider starting to write in a journal - may not be for everyone, but can be a helpful and healthy way to release some of the emotion that can be overwhelming at times).
Godspeed.